6640369645 has 32 divisors (see below), whose sum is σ = 9822597120. Its totient is φ = 4196586240.

The previous prime is 6640369607. The next prime is 6640369661. The reversal of 6640369645 is 5469630466.

It is a happy number.

It is not a de Polignac number, because 6640369645 - 2²¹ = 6638272493 is a prime.

It is a super-3 number, since 3×6640369645³ (a number of 30 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 289716 + ... + 311794.

It is an arithmetic number, because the mean of its divisors is an integer number (306956160).

Almost surely, 2^6640369645 is an apocalyptic number.

6640369645 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

6640369645 is a deficient number, since it is larger than the sum of its proper divisors (3182227475).

6640369645 is a wasteful number, since it uses less digits than its factorization.

6640369645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22765.

The product of its (nonzero) digits is 2799360, while the sum is 49.

The square root of 6640369645 is about 81488.4632632129. The cubic root of 6640369645 is about 1879.5941523398.

The spelling of 6640369645 in words is "six billion, six hundred forty million, three hundred sixty-nine thousand, six hundred forty-five".